A molecule found in the tobacco plant's natural defence mechanisms could be useful in killing cancer cells in humans, according to an Australian research.

Scientists at the La Trobe University's Institute for Molecular Science have identified that a molecule occurring in the flower of the tobacco plant that fights off fungi and bacteria also has the ability to identify and destroy cancerous cells while leaving healthy cells unscathed.

The defence molecule, called NaD1, works by forming a pincer-like structure that grips onto lipids present in the membrane of cancer cells and rips it open, causing the cell to expel its contents and explode.

The results have been published in the journal eLife.

"This is the holy grail - to develop specific agents which will only target cancer and not the normal healthy cells," lead investigator Mark Hulett said.

"There is some irony in the fact that a powerful defence mechanism against cancer is found in the flower of a species of ornamental tobacco plant, but this is a welcome discovery, whatever the origin," Hulett said.

"The next step is to undertake pre-clinical studies to determine what role NaD1 might be able to play in treating cancer. The preclinical work is being conducted by the Melbourne biotechnology company Hexima. So far the preliminary trials have looked promising.

"We are confident there is potential for this discovery to translate to therapeutic use in humans.

"One of the biggest issues with current cancer therapies is that the effect of the treatment is indiscriminate," Hulett said.

"In contrast, we've found NaD1 can target cancerous cells and has little or no effect on those that are healthy."

Hulett said scientists have known for some time about the molecules that form the first line of defence against microbial invasion in all plant and animal species. Until now nobody has known how the molecules actually did their job.

"We've discovered the workings of this universal defence process, which could also potentially be harnessed for the development of other therapeutic applications, including antibiotic treatment for microbial infections," he said.

The discovery is the result of a multidisciplinary collaboration between scientists from Hulett's laboratory in cancer biology and Marc Kvansakul's laboratory in structural biology at La Trobe University.